I would argue that the benefits of such a capability goes beyond just typing faster.
I regularly use tons of acronyms and add tables of accronyms and their definitions at the beginning of documents that I want to share with people. I want to be able to create a note specifically for initials/accronyms such as
AI :: Artificial intelligence
ML :: Machine learning
etc.
Then, when creating another document, I can use these predefined initials using a specific code such as AI (:AI:). The result would appear as AI (Artificial intelligence)